This relates to a labeled article which has a label applied during a molding process, and to a method of making such an article. The labeled article is highly resistant to harsh environmental conditions to which it may be subjected in use. More particularly, the labeled article resists deterioration from mechanical wear, chemicals, moisture, and abrasion.
Product manufacturers place a high value on the ability to deliver molded articles with high quality graphic surfaces. This has traditionally required a trade-off between the quality of the images, the permanence of the images, and the print media utilized. High quality graphic surfaces have been achieved by lithographically printing adhesive labels, and then applying the labels to the articles. Articles made in this way have suffered from poor label adhesion and degraded label appearance. The loss of adhesion that usually results from aging is exacerbated by environmental factors, such as moisture and large changes in temperature. This loss of adhesion is particularly acute in outdoor and automotive applications. Clearly, it is desirable that labels remain on labeled products and that the graphics on the labels remain esthetically pleasing. Further, it may also be important that the labels on the products remain attached to the products and convey needed information, such as for example product warning messages.
In-mold techniques have been developed to address these problems with articles that are manufactured in a molding process. In an in-mold labeling process, graphics, including text, are typically printed on polymer films that are compatible with the polymer material that is to be used in the molding process. It has been common to use screen-printing techniques to print on clear polymer film materials that are compatible with the polymer material from which the part is molded. The clear film allows the underlying molded polymer to show through. Many in-mold techniques have also used complex, multi-layered films to achieve a satisfactory product. The printed film label is normally placed into the mold so that the molten polymer material flows over the ink, which is trapped between the film and the polymer material. Temperatures and pressures characteristic of this technique necessitate screen printing inks that can withstand this process. The graphic detail quality achievable by these techniques is limited by the environment in which said inks must remain stable and not wash out or flow with the molten polymer. Further, screen printing by separately depositing each of a series of colors increases the cost of the product.
An improved in-mold and in-line decorating method is disclosed in U.S. Pub. App. 2007/0079928, published Apr. 12, 2007. This application teaches using a single sheet layer that allows the placement of the highest possible quality graphics into the surface of products made from a variety of moldable thermoplastic, thermoset, and vulcanizable materials using a variety of molding processes. A label-sized sheet of micro-porous material is printed using a four color process, and the printed sheet is inserted into a mold. The article is then molded, producing a finished, labeled part. While this process represents an advance over the prior art, the surface of the micro-porous sheet is exposed to the environment to which the article is subjected.
It is desired that a labeled article and method of making the article be provided in which the labeled article resists deterioration from exposure to a harsh environment.